Antioxidants abrogate the ability of arsenicals to induce ROS A) Quantitative comparison of relative DCFDA fluorescence following 10 μM As(III) treatment alone or after pretreatment with 2.5 mM melatonin, 5 mM KI, peg-SOD, or peg-catalase (N=3). B) Quantitative comparison of relative DCFDA fluorescence following 500 nM MMA(III) treatment alone or after pretreatment with 2.5 mM melatonin, 5 mM KI, peg-SOD, or peg-catalase (N=3). (*) Marks statistically significant increase in relative fluorescence when compared with control UROtsa (p≤0.05). (†) Marks statisticallysignificant decrease in relative fluorescence when compared with arsenical-treated UROtsa (p≤0.05).